This invention relates to devices for muffling and silencing of noises in fluid pressure exhausts and more particularly to silencers of mufflers for the exhaust systems of compressed air operated power cylinders, tools or the like.
1. Field of the Invention
This invention is particularly directed to improved and novel muffling devices for silencing exhaust noises by directing exhaust gases under pressure through new and improved energy absorbing cartridges to atmosphere with axial and radial flow occurring in different embodiments of the muffling devices.
2. Description of the Prior Art
Heretofore, mufflers have been used for the dissipation of exhaust noises wherein the exhaust stream of gases is diverted by fins or ribs of a spider means within the mufflers. Other mufflers have dissipated exhaust noises of an exhaust system in a silencing chamber by the utilization of porous walls through which the exhaust fluid is diffused.
Applicant's U.S. Pat. No. 4,316,523 is believed to be the closest prior art known.
Other patents of interest comprise the following references cited in U.S. Pat. No. 4,316,523.
U.S. Pat. No. 763,626 discloses a muffler for moving a gas to atmosphere from an engine which employs a spring biased valve movably guided on a shaft.
U.S. Pat. No. 797,681 discloses a muffler device employing a relief means for providing an alternate route for the exhaust gas in response to an increase in the pressure of the gas within the muffler.
U.S. Pat. No. 1,479,714 discloses a muffler for exhaust gases from an internal combustion engine employing an alternate route when the gas pressure reaches a given value. The alternate route is controlled by a weighted door hingedly secured to the end of the alternate route.
U.S. Pat. No. 1,512,210 discloses a muffler for an internal combustion engine employing an alternate route which opens up in response to increased pressure within the muffler which alternate route is controlled by a lever arm and spring mechanism.
U.S. Pat. No. 1,666,005 discloses a muffler employing a spring loaded valve for controlling the escape of gases under pressure.
U.S. Pat. No. 3,208,551 discloses an air silencer for pneumatic devices which includes a cylindrically shaped shell having circumferential slots therein to provide air outlets in communication with the interior of the shell and an air restricting cartridge made of a screen material for muffling the sound of the moving air.
U.S. Pat. No. 3,219,144 discloses a muffler for an internal combustion engine which includes spring biased means for controlling an adjustable exhaust port in response to the pressure of the exhaust gas.
U.S. Pat. No. 3,380,553 discloses an exhaust muffler wherein the noise level of the fluid under pressure moving therethrough is reduced by reducing the velocity of the fluid and causing the fluid to expand thereby expending energy.
U.S. Pat. No. 3,612,214 discloses a safety relief for an air silencer for a pneumatic device which includes means for redirecting the flow of air if the pressure within the silencer reaches a predetermined level.
U.S. Pat. No. 3,672,465 discloses an air exhaust silencer employing baffle members made of a porous material wherein the air is broken up and exhausted therethrough to atmosphere.
Applicant has disclosed herein an energy absorbing cartridge employing a novel arrangement of juxtapositioned layers of wire cloth and soft resilient energy absorbing materials to reduce exhaust air noises and to induce a breathing action which provides a self-cleaning action to prevent loading and premature failure of the cartridge assembly. Two new components, a liner and an insert, are incorporated in this new design to provide a low air pressure drop barrier to trap foreign particles before they reach the resilient parts of the cartridge.